Re: [Qemu-devel] [PATCH 4/8] virtio: add detach element for packed ring(1.1)

[Jason Wang <jasowang@redhat.com>]

On 2018年04月04日 20:54, wexu@redhat.com wrote:
> From: Wei Xu <wexu@redhat.com>
>
> helper for packed ring

It's odd and hard to review if you put detach patch first. I think this 
patch needs to be reordered after the implementation of pop/map.

Thanks

> Signed-off-by: Wei Xu <wexu@redhat.com>
> ---
>   hw/virtio/virtio.c | 21 +++++++++++++++++++--
>   1 file changed, 19 insertions(+), 2 deletions(-)
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 478df3d..fdee40f 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -561,6 +561,20 @@ static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
>                            elem->out_sg[i].iov_len);
>   }
>   
> +static void virtqueue_detach_element_split(VirtQueue *vq,
> +                            const VirtQueueElement *elem, unsigned int len)
> +{
> +    vq->inuse--;
> +    virtqueue_unmap_sg(vq, elem, len);
> +}
> +
> +static void virtqueue_detach_element_packed(VirtQueue *vq,
> +                            const VirtQueueElement *elem, unsigned int len)
> +{
> +    vq->inuse -= elem->count;
> +    virtqueue_unmap_sg(vq, elem, len);
> +}
> +
>   /* virtqueue_detach_element:
>    * @vq: The #VirtQueue
>    * @elem: The #VirtQueueElement
> @@ -573,8 +587,11 @@ static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
>   void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
>                                 unsigned int len)
>   {
> -    vq->inuse--;
> -    virtqueue_unmap_sg(vq, elem, len);
> +    if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
> +        virtqueue_detach_element_packed(vq, elem, len);
> +    } else {
> +        virtqueue_detach_element_split(vq, elem, len);
> +    }
>   }
>   
>   /* virtqueue_unpop: